package org.apache.lucene.search;

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * Expert: Delegating scoring implementation. Useful in {@link
 * Query#getSimilarity(Searcher)} implementations, to override only certain
 * methods of a Searcher's Similiarty implementation..
 */
public class SimilarityDelegator extends Similarity {

	private Similarity delegee;

	/**
	 * Construct a {@link Similarity} that delegates all methods to another.
	 * 
	 * @param delegee
	 *            the Similarity implementation to delegate to
	 */
	public SimilarityDelegator(Similarity delegee) {
		this.delegee = delegee;
	}

	public float lengthNorm(String fieldName, int numTerms) {
		return delegee.lengthNorm(fieldName, numTerms);
	}

	public float queryNorm(float sumOfSquaredWeights) {
		return delegee.queryNorm(sumOfSquaredWeights);
	}

	public float tf(float freq) {
		return delegee.tf(freq);
	}

	public float sloppyFreq(int distance) {
		return delegee.sloppyFreq(distance);
	}

	public float idf(int docFreq, int numDocs) {
		return delegee.idf(docFreq, numDocs);
	}

	public float coord(int overlap, int maxOverlap) {
		return delegee.coord(overlap, maxOverlap);
	}

}
